The purpose of these studies is to provide data of suitable quality and integrity to support applications to the U.S. Food and Drug Administration (FDA) and other regulatory agencies. The objective of the studies is to determine the safety profile and to establish a maximum tolerated dose (MTD) and no observed adverse effect level (NOAEL) of Cytisine in various definitive toxicology and safety pharmacology studies to support an Investigational New Drug (IND) application for this compound. The GLP studies will be performed in accordance with the U.S. FDA ?Good Laboratory Practice for Nonclinical Laboratory Studies? (GLP) as described in 21 CFR Part 58. Information from this study may be used to determine the suitability of the proposed human dose.